1. Field of the Invention
The present invention relates to an adaptive array antenna transceiver apparatus that carries out transceiving a wireless signal using an adaptive array antenna, and in particular, in a communication system using a signals having different frequencies for transmission and reception, such as the FDD (Frequency Division Duplex) systems, relates to an adaptive array antenna transceiver apparatus for automatically calibrating the amplitude and phase differences between branches of the antenna for the respective transmitter and receiver.
This application is based on patent applications No. Hei-11-355995, Hei 11-365352, and 2000-113316 filed in Japan, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Accompanying the rapid increasing use of mobile communication systems such as cellular telephones and PHS (Personal Handyphone System), it has become necessary to secure communication channels for as many subscribers as possible in a limited frequency band.
In order to do this, using a method of allocating as necessary a particular channel (multichannel access method) for multiple subscribers in mobile communications is the currently the main practice.
In the present mobile communication systems represented by cellular systems or PHS, for example, the TDMA (Time Division Multiple Access) is mainly used as the multichannel access method. Among these, the FDD system is used to enlarge the transmission area in GSM (Global System for Mobile Communications) and PDC (Personal Digital Cellular Telecommunication System), represented by cellular telephone systems.
However, in order to increase the efficiency of the use of the frequencies in a wireless area, it is necessary to decrease the influence of interference from adjacent cells. As technologies for decreasing the interference, the adaptive array antenna is known. This type of technology is disclosed in Citation 1, Monzingo et al., Introduction to Adaptive Arrays, John Willy and Sons, New York, 1980.
In an adaptive array antenna, an array antenna is formed by a plurality of antenna elements arranged in an array. In addition, the radiation pattern of the array antenna is controlled by weighting the amplitude and phase with respect to an input signal for each of the branches of the array antenna. This means that the null direction of the radiation pattern of the array antenna is formed in the direction of the interference, and thus the influence if the interference is decreased.
An apparatus combining an adaptive array antenna and an FDD system is formed as shown in FIG. 34.
In recent years, considering the ease and flexibility of control, the general method for the control of the amplitude and phase necessary for adaptive arrays is realized by digital signal processing, using a processor such as a DSP (Digital Signal Processor), in the baseband. This is disclosed in T. Ohgane, et al., xe2x80x9cImplementation of a CMA Adaptive array for high speed GMSK transmission in mobile communicationsxe2x80x9d, IEEE Trans., Vol. 42, No. 3, pp. 282-288, August, 1993.
Therefore, in the case of realizing an adaptive array antenna by control of the baseband, a transmitter and receiver are necessary for each antenna of the array antenna. For the transmitter and receiver using this type of adaptive array antenna, ideally the amplitudes and phases between each of the branches are equal. However, in practice due to individual differences in high frequency circuits and cables of the electrical amplifiers, etc., fluctuations of the temperature characteristics of the installation location, etc., frequently the amplitudes and phases between branches are different.
Due to the influence of this type of difference in amplitude and phase, in the radiation pattern of an adaptive array antenna, a shrinking in the null direction and a bulging of the side lobe occurs with respect to the ideal radiation pattern, and this becomes a factor causing deterioration of the inherent interference suppression characteristics of the adaptive array antenna. This is disclosed for example in Citation 3, J. Litva et al., Digital Beamforming in Wireless Communications, Artech House Publishers, 1996.
An example of this phenomenon is explained referring to FIG. 31 and FIG. 32. FIG. 31 shows the structure of the array antenna and the radiation pattern, and FIG. 32 shows the relationship of the amplitude and phase error to the null depth. That is, using as a reference the case in which the amplitude and phase shown in FIG. 31 are given as ideal conditions for each of three array antenna elements arranged in a circle shown in FIG. 31, the null depth of the radiation pattern in the case that the amplitude and phase of each element deviates from the ideal conditions is shown in FIG. 32.
Under the ideal conditions, a radiation pattern having a null direction at 180xc2x0 is formed, as shown in FIG. 32, and the depth of the null direction is becomes very large. However, in the case that the amplitude and phase of each element deviates from the ideal conditions serving as the reference, the radiation pattern of the array antenna deteriorates, and the depth in the null direction as shown in FIG. 32 decreases depending on the amplitude error and the phase error.
Therefore, in order to make the radiation pattern of the transmission and the radiation pattern in the reception of the adaptive array antenna agree when using an FDD system having a transmission frequency and reception frequency that are different, technology for calibrating the amplitude and phase between each of the branches of the array antenna becomes necessary. In addition, in the case that the adaptive array antenna in the FDD system is used, because the frequency of transmission and reception are different, the weighting coefficient for each element of the adaptive array antenna required during reception cannot be applied during transmission as-is.
Therefore, normally in order to determine that weighting coefficient of the adaptive array antenna during transmission, it is necessary to estimate the direction of the desired signal and the interference signal using some kind of technology that estimates the incoming direction during reception, and the radiation pattern is controlled by determining the weighting coefficient during transmission using this information about direction. Thus, in order to use an adaptive array in an FDD system, respectively carrying out individual calibration during reception and during transmission is necessary.
Conventionally, in the case of calibrating the amplitude and phase of each of the transmitters and receivers, a reference signal for calibration output by an oscillator built into the apparatus is used. This type of technology is disclosed, for example, in Citation 4, H. Steyscal et al., xe2x80x9cDigital Beamforming for Radarsxe2x80x9d, in Microwave Journal, vol. 32, no. 1, pp. 122-136.
The calibration circuit for such a conventional example is shown in FIG. 33. The calibration procedure in the case of using the calibration circuit shown in FIG. 33 is as follows:
(1) A reference signal from a reference signal oscillator is sent as a common signal to each of the branches to the receivers of each of the branches via a coupler having a branching means. The calibration value for each receiver is found using the value obtained at the receiver of each of the branches and the reference value. The value of a particular branch determined in advance and detected by the receiver is used as this reference value.
(2) The signal output from the transmitter is sent to the receiver via an attenuator, and the calibration value for all transmitters and receivers is found for each of the branches using the value obtained for each of the branches and the reference value. The reference value used here is the value obtained by the receiver of the branch serving as the reference when the calibration value of the receiver is found in step 1 above.
(3) The calibration value of the receiver found in step 1 above is subtracted from the calibration value for all transmitters and receivers found in step 2 above, and the calibration value for each transmitter is found.
In the above manner, by using the calibration circuit in FIG. 33, the amplitude and phase between each of the branches of the array antenna in the apparatus can be calibrated.
However, because the frequencies of the transmitter and receiver differ in the case of an FDD system, the receiver cannot measure the signal output from the transmitter, and thus even if a calibration circuit such as that shown in FIG. 33 is used, the procedure in step 2 above cannot be carried out. Therefore, in the case of using the conventional calibration circuit, only calibration of the receiver can be carried out, and the problem occurs that the amplitude error and phase error on the transmitter side cannot be cancelled. In addition, the conventional calibration circuit realizes calibration between apparatuses, and cannot carry out calibration between antenna elements.
In contrast, in the case of calibrating the amplitude and phase between each of the branches of the array antenna apparatus so as to include the variation in the amplitude and phase of the antenna elements, a method is used wherein a signal arriving from a distant field is received or a signal transmitted from an array antenna at a distance field is received, and the phase is rotated in sequence using a phase shifter for each of the branches. This technology is disclosed, for example, in Citation 5, Mano and Kataki, xe2x80x9cAmplitude and phase measurement method for elements of a phased array antennaxe2x80x9d, Proceedings of the Electronic Communication Symposium (B), vol. J-65-B, no. 5, pp. 555-560 [in Japanese].
However, in mobile communication, for example, the base stations are not necessarily arranged in a regular pattern, and each base station is placed at positions to cancel the blind zones in a communication area and at positions suitably determined depending on increasing traffic. In the case of using an element field vector rotation method described above at each base station for mobile communication, the base station and the standard station must satisfy line-of-site conditions. Therefore, in an environment such as mobile communications, calibrating the amplitude and phase between each of the branches of an array antenna as far as possible within the apparatus itself is preferable.
In addition, a method that carries out calibration of the antenna and the transmitters and receivers connected thereto by transmitting and receiving a signal between the antenna elements of the array antenna is disclosed, for example, in Citation 6, H. M. Aumann et al., xe2x80x9cPhased Array Antenna Calibration and Pattern Prediction Using Mutual Coupling Measurementsxe2x80x9d, IEEE Trans. on AP-37, no. 7, pp. 844-850, July 1989.
Citation 6 will be explained referring to FIGS. 35A and 35B. In this method, as shown in FIG. 35A, each of the antenna elements is arranged so as to form, for example, a hexagon, and at the same time are arranged so as to be equally spaced when the adjacent antennal elements are viewed from a reference element (in this case, denoted #m). In this case, the mutual coupling between the adjacent antenna elements viewed from the reference element can be treated as identical. Under this condition, by transmitting and receiving a signal between the adjacent antennal elements and the reference element, as shown in FIG. 35B, the differences between amplitude and phase between the transmitters and the receivers can be compensated.
However, many times the arrangement of the antenna elements in practice is a straight line or circle, and in these actual arrangements, equalizing the mutual coupling between the used antennas is difficult. In addition, in order to apply this method, all of the elements must satisfy the conditions described above, and a plurality of antennas for calibration is necessary. In the case of using this method in an FDD system, because the transmitting and receiving frequencies are different, there is the problem that a signal cannot be simply transmitted and received between adjacent antennas.
An object of the present invention is to provide an adaptive array antenna transceiver apparatus that can separately and simply calibrate, in an array antenna apparatus, both the transmitters and receivers of an apparatus that includes the antenna power source even in the case that the transmitting frequency and the reception frequency of the array antenna are different.
In order to attain this objective, in an adaptive array transceiver apparatus providing an array antenna comprising a plurality of antenna elements, transmitters and receivers in the same number as the antenna elements of the array antenna, a transmitter/receiver common-use device connecting the respective transmitters and receivers to each of the antenna elements, and a radiation pattern control processor that controls the radiation pattern of the array antenna by synthesizing the output of the plurality of receivers by weighting the amplitude and phase with respect to a signal input from each respective antenna element to the plurality of receivers, and at the same time the reception frequency of the receivers is different from the transmitting frequency of the transmitters, the present invention provides a local signal generator that outputs a signal having a frequency that corresponds to the difference between the reception frequency of the receivers and the transmitting frequency of the transmitters, a branching device that separates and extracts a part of the signals from the output of the plurality of transmitters, a first switch that selects the signal output from any one of the plurality of transmitters, a frequency converter that converts the frequency of the signal selected by the first switch by using the signal output by the local signal generator, a second switch that inputs signals output by the frequency converter and selectively outputs them to any one of the plurality of paths corresponding to the plurality of receivers, a third switch that selectively inputs into each of the receivers a reception signal from the antenna elements and a signal from the second switch, and a calibration control circuit that controls the connection state of the first switch, the second switch, and the third switch, inputs the amplitude and phase values obtained at the receivers, and finds the calibration value of each of the branches of the array antenna.
In this first aspect of the adaptive array antenna transceiver apparatus, the signals output by any one of the plurality of transmitters is extracted by a branching device (for example a coupler), selected by the first switch, and input to the frequency converter. The frequency converter converts the frequency of the signal selected by the first switch using a signal output by the local signal generator.
In addition, the frequency of the signal output by the local signal generator corresponds to the difference between the reception frequency of the receivers and the transmission frequency of the transmitters. For example, in the case that the transmission frequency of the transmitter is f1 and the reception frequency of the receiver is f2, and there is a relationship f1 greater than f2, the frequency of the signal output by the local signal generator becomes f1xe2x88x92f2. Therefore, when a signal having a frequency f1 output from the transmitter is input into a frequency converter, a signal having a frequency f2 is obtained at the output of the frequency converter. The frequency f2 of this signal is the same as reception frequency f2 of the receivers, and thus if this signal is input into each of the receivers, the amplitude and phase of the signal can be measured at these receivers.
The second switch inputs the signal output by the frequency converter and selectively outputs it to any one of a plurality of paths corresponding to the plurality of receivers. The third switch selectively inputs into each receiver the reception signal from the antenna elements and the signals from the second switch.
Therefore, by switching the first switch, the second switch, and the third switch, the transmission signal from the transmitter provided on any one of the branches of the array antenna can be input into the transmitter of any one of the branches after it matches the frequency.
The calibration control circuit carries out the control of the first switch, the second switch, and the third switch. In addition, the calibration control circuit inputs the amplitude and phase values obtained at the receivers and finds the calibration value for each of the branches of the antenna.
According to the first aspect of the adaptive array antenna transceiver apparatus, even in the case that the reception frequency of the receiver and the transmission frequency of the transmitter are different, the amplitude and phase values can be measured by inputting the signal output by the transmitter into the receiver, and thus calibration of the transmitter can be carried out without calibrating the receiver.
In addition, in the present invention, in the first aspect of the adaptive array antenna transceiver apparatus, the calibration control circuit selects in sequence the signals output from the respective plurality of transmitters by the first switch, and at the same time, controls the second switch and the third switch, inputs the signal that has been frequency converted by the frequency converter into the receiver of the particular branch assigned in advance to serve as a reference, and calculates, as the calibration value of the transmission system of each of the branches, a amplitude and phase ration between the plurality of values measured at the transceiver of each branches and the values measured at the transceiver of the particular branch assigned in advance to serve as the reference.
The components of the transmitter, the components of the receiver, and the components dependent temperature characteristics are included in the amplitude and phase values that are obtained by detecting the signal output by the transmitter at the receiver. Because the ratio of the amplitude and phase values obtained by measuring the signals from the transmitter of each of the branches at a particular receiver to the amplitude and phase values obtained by measuring a signal from the transmitter of the branch serving as the reference is found, the components of the common receivers and the components of the temperature characteristics are offset in the amplitude and phase values of each of the branches are cancelled, and the components of the amplitude and phase values of only the transmitters can be obtained as calibration values.
In addition, in the present invention, in the first aspect of the adaptive antenna transceiver apparatus, the calibration circuit selects a signal output by the transmitter of a particular branch assigned in advance to serve as a reference, and at the same time, by controlling the second switch and the third switch, the signals that have been frequency converted by the frequency converter are input in sequence into the receiver of each of the branches, and calculates, as the calibration value of the reception system of each of the branches, a amplitude and phase ration between the plurality of values measured at the receiver of each branches and the values measured at the receiver of the particular branch assigned in advance to serve as the reference.
The component of the transmitter, the component of the receiver, and the components dependent on the temperature characteristics are included in the amplitude and phase values obtained by detecting the signal output by a transmitter at a receiver. Because the ratio of the amplitude and phase values obtained by measuring the ratio of the amplitude and phase values obtained by measuring the signals from a particular transmitter to the amplitude and phase values measured at the receiver of the branch serving as the reference is found, the components of the common transmitters and the components of the temperature characteristics are cancelled in the amplitude and phase values of each of the branches, and the components of the amplitude and phase values of only the receiver are obtained as the calibration values.
Furthermore, in an adaptive array transceiver apparatus providing an array antenna comprising a plurality of antenna elements of the array antenna, transmitters and receivers in the same number as the antenna elements of the array antenna, transmitter/receiver common-use devices connecting the respective transmitters and receivers to each of the antenna elements, and a radiation pattern control calculation circuit that controls the radiation pattern of the array antenna by synthesizing the output of the plurality of receivers by weighting the amplitude and phase with respect to the signals input from each of the respective antenna elements to the plurality of receivers, and at the same time the reception frequency of the receivers is different from the transmitting frequency of the signal applied to the antenna elements from the transmitter, the present invention provides a local signal generator that outputs a signal having a frequency that corresponds to the difference between the reception frequency and the transmitting frequency, a first frequency converter that converts the frequency of the signal having the same frequency as the reception frequency output from each of the plurality of transmitters using a signal output by the local signal generator, a first branching device that separates and extracts a part of the signals from the output of the plurality of transmitters after conversion by the first frequency converter, a second branching device that separates and extracts a part of a signal from the output of one transmitter before conversion by the first frequency converter, a first switch that selects one signal input by any one of the plurality of transmitters into the first branching device, a second frequency converter that converts the frequency of the signal selected by the first switch by using the signal output by the local signal generator, a second switch that inputs signals output by the second branching device and selectively outputs them to one of the plurality of paths corresponding to the plurality of receivers, a third switch that selectively inputs into each of the receivers a reception signal from the antenna elements, a signal from the second switch, and a signal from the second frequency converter, and a calibration control circuit that controls the connection state of the first switch, the second switch, and the third switch, inputs the amplitude and phase values obtained at the receivers, and finds the calibration value of each of the branches of the array antenna.
In the second aspect of the adaptive transceiver apparatus, the frequency of the signal output by each of the transmitters is identical to the reception frequency of the receivers, but the signals output by each of the transmitters are frequency converted by the first frequency converter and applied to the antenna elements as transmission signals. Thus, like the first aspect, the transmission frequency and the reception frequency of the receivers are different.
The first branching device separates and extracts a part of the transmission signal after conversion by the first frequency converter. The first switch selects a signal (the signal after conversion by the first frequency converter) from the transmitter of any one of the branches, and inputs this to the second frequency converter. The second frequency converter converts the frequency of the signal selected by the first switch using the signal output by the local signal generator.
In addition, the frequency of the signal output by the local signal generator corresponds to the difference between the reception frequency of the receiver and the transmission frequency. For example, in the case that the transmission frequency of the signal applied to the antenna elements is f1, the reception frequency of the receiver is f2, and the relationship between these frequencies is f1 greater than f2, the frequency of the signal output by the local signal generator becomes f1xe2x88x92f2.
Therefore, when the signal that is input from the transmitter, passes through the first frequency converter, and has the frequency f1, is input into the second frequency converter, a signal having a frequency of f2 is obtained at the output of the second frequency converter. The frequency f2 of this signal is identical to the frequency f2 of the reception frequency of the receiver, and thus, if this signal is input into each receiver, the amplitude and phase at the receiver can be measured.
In this example, the frequency of the signal output from each of the transmitters is identical to the reception frequency of the receivers, and thus in the case that the signal from the transmitter is extracted before passing through the first frequency converter, the amplitude and phase values at the receiver can be measured without converting the frequency of this signal.
Thus, the second switch extracts from the output of the transmitter of one branch the signal before conversion by the first frequency converter using the second branching device, and selectively outputs this to one of the plurality of paths corresponding to the plurality of receivers. The third switch selectively inputs into each receiver the reception signal from the antenna elements, the signal from the second switch, and the signal from the second frequency converter.
Therefore, by switching the first switch, the second switch, and the third switch, the transmission signal from the transmitter provided on any one of the branches of the array antenna can be input into the receiver of any one of the branches after it matches the frequency.
The calibration control circuit carries out the control of the first switch, the second switch, and the third switch. In addition, the calibration control circuit inputs the amplitude and phase values obtained at the receiver and finds the calibration value of each of the branches of the array antenna.
In addition, the second aspect of the adaptive array antenna transceiver apparatus can carry out calibration of the transmitter without calibrating the receiver because the amplitude and phase values can be measured by inputting the signals output by the transmitter to the receiver even in the case that the reception frequency and the transmitting frequency are different.
In addition, in the present invention, in the second aspect of the adaptive array antenna transceiver apparatus, the calibration control circuit selects in sequence signals output from each of the plurality of transmitters using the first switch, and at the same time, controls the second switch and the third switch, inputs into the receiver of a particular branch assigned in advance to serve as a reference signal a signal that has been frequency converted by the second frequency converter, and calculates as the calibration value of the transmitter system of each of the branches the ratio of the plurality of the amplitude and phase values measured for the respective signals from the transmitters of each of the branches to the amplitude and phase values measured for the signal from the transmitter of a particular branch assigned in advance to serve as a reference.
The component of the transmitter, the component of the receiver, and the components of the temperature characteristics are included in the amplitude and phase values obtained by detecting the signal output by the transmitter at the receiver. The ratio of the amplitude and phase values obtained by measuring the signal from the transmitter of each of the branches at a particular receiver and the amplitude and phase values obtained by measuring the signal from the transmitter of the branch that serves as the reference, and thus the components of the common receivers and the components dependent on temperature characteristics are cancelled in the amplitude and phase values of each of the branches, and the component of the amplitude and phase values of only the transmitter is obtained as the calibration value.
In addition, in the present invention, in the second aspect of adaptive array antenna transceiver apparatus, the calibration control circuit extracts the signals output by the transmitter of a particular branch assigned in advance to serve as the reference using the second branching device, inputs these in sequence to the receivers of each of the branches via the second switch and the third switch, and calculates as the calibration value of the reception system of each of the branches the ratio of the plurality of amplitude and phase values measured at the respective receivers of each of the branches and the amplitude and phase values measured at the receiver of the particular branch assigned in advance to serve as the reference.
The component of the transmitter, the component of the receiver, and the components of the temperature characteristics are included in the amplitude and phase values obtained by detecting the signal output by the transmitter at the receiver. The ratio of the amplitude and phase values obtained by measuring the signal from the particular transmitter at the receiver of each of the branches and the amplitude and phase values measured at the receiver of the branch that serves as the reference is found, and thus the component of the common transmitters and the components dependent on the temperature characteristics are cancelled in the amplitude and phase values of each of the branches, and the component of the amplitude and phase values of only the receiver is obtained as the calibration value.
Furthermore, in an adaptive array transceiver apparatus providing an array antenna comprising a plurality of antenna elements, transmitters and receivers in the same number as the antenna elements of the array antenna, transmitter/receiver common-use devices connecting the respective transmitters and receivers to each of the antenna elements, and a radiation pattern control calculation circuit that controls the radiation pattern of the array antenna by synthesizing the output of the plurality of receivers by weighting the amplitude and phase with respect to a signal input from each respective antenna element to the plurality of receivers, and at the same time the reception frequency of the receivers is different from the transmitting frequency of the transmitters, the present invention provides a local signal generator that outputs a signal having a frequency that corresponds to the difference between the reception frequency of the receivers and the transmitting frequency of the transmitters, a branching device that separates and extracts a part of the signals from the plurality respective of transmitters, a plurality of first switches that inputs and selects one of the output signals of the respective branching devices from two adjacent branches in the arrangement of the branches of the array antenna determined in advance, a frequency converter that converts the frequency of the signal selected by the first switch by using the signal output by the local signal generator, a plurality of second switches that input signals output by the frequency converter for each of the plurality of branches of the array antenna and selectively outputs this to one of the two branches adjacent to each other, a third switch that selects one of the reception signals from the antenna element of the relevant branch, a signal from the second switch included in the relevant branch, and a signal from the second switch included in the adjacent branch and inputs it into one of the receivers, and a calibration control circuit that controls the connection state of the first switch, the second switch, and the third switch, inputs the amplitude and phase values obtained at the receiver, and finds the calibration value of each of the branches of the array antenna.
In a third aspect of the adaptive array antenna, a first switch inputs the output signals of said branching device respectively from two branches that are adjacent to each other, and selects one of them. Moreover, the two branches that are adjacent in this case do not necessarily conform to the actual arrangement of the antenna elements, and the arrangement of the branches that the first switch selects can be determined arbitrarily.
The frequency converter converts the frequencies of the signal selected by the first switch in each of the branches using the signal that the local signal generator outputs.
In addition, the frequency of the signal output by the local signal generator corresponds to the difference between the reception frequency of the receiver and the transmission frequency of the transmitter. For example, in the case that the transmission frequency of the transmitter is f1, the reception frequency of the receiver is f2, and the relationship therebetween is (f1 greater than f2), then the frequency of the signal output by the local signal generator is (f1xe2x88x92f2). Therefore, when the signal output from the receiver and having a frequency of f1 is input into the frequency converter, a signal having a frequency of f2 is obtained at the output of the frequency converter. The frequency f2 of this signal is the same as the reception frequency f2 of the receivers, and thus if this signal is input into each of the receivers, the amplitude and phase of the signal can be measured at these receivers.
The second switch inputs a signal output by the frequency converter for the respective plurality of branches of the array antenna, and selectively outputs it to one of the paths among the two branches that are adjacent to each other.
For the respective plurality of branches of the array antenna, the third switch selects among the reception signals from the antenna elements of the relevant branch, the second switch belonging to the relevant branch, or the signal from the second switch belonging to the adjacent branch, and inputs them into one receiver.
Therefore, by switching the first switch, the second switch, and the third switch, the transmission signal from the transmitter provided on any one of the branches of the array antenna can be input into the receiver of any one of the branches after it matches the frequency.
The calibration control circuit carries out the control of the first switch, the second switch, and the third switch. In addition, the calibration control circuit inputs the amplitude and phase values obtained at the receiver and finds the calibration value for each of the branches of the antenna.
According to the third aspect of the adaptive array antenna transceiver apparatus, even in the case that the reception frequency of the receiver and the transmission frequency of the transmitter are different, the signal output by the transmitter is input into the receiver, and the amplitude and phase values can be measured, and thus not only calibration of the receiver, but calibration of the transmitter can be carried out.
In addition, in the third aspect of the adaptive array transceiver apparatus, the calibration control circuit alternately selects by the first switch the signals output by the transmitters of two adjacent branches at each of the adjacent branches, and at the same time, controls the second switch and the third switch, inputs the signal frequency converted by the frequency converter into one receiver assigned in advance among the two branches, finds as the first ratio the ratio of the respectively measured values of the amplitude and phase for the signals from the transmitters of the two branches, and at the same time, for branches other than the branch assigned in advance to serve as the reference, the first ratio found at the relevant branch is calibrated using the first ratio found at the other branches, and the calibration value of the transmitting system of each of the branches is calculated.
The signals from the transmitters of two adjacent branches are alternately selected by the first switch and input into the receiver common to one branch, and thereby the two amplitude and phase values are obtained. The ratio for these two amplitudes and phase values serves as the first ratio. The first ratio is found at each of the respective adjacent branches.
However, amplitude and phase value components related to the transmitter of the two branches are included in the first ratio found between two adjacent branches. Thus, for branches other than that assigned in advance to serve as the reference, the first ratio found at the relevant branch is calibrated using the first ratio found from the other branches.
By this calibration, the first ratio of each of the branches is unified with the ratio of the amplitude and phase values of the transmitter of the relevant branch with respect to the amplitude and phase value components of the transmitter of a particular branch assigned to serve as a reference. Therefore, the first ratio of each of the branches can be used as a calibration value for the amplitude and phase value components of each of the transmitters.
In addition, in the present invention, in the third aspect of the adaptive array antenna transceiver apparatus, the calibration control circuit selects the signal output by the one transmitter assigned in advance among two adjacent branches for each adjacent branch by the first switch, and at the same time, controls the second switch and the third switch, alternately inputs the signal that has been frequency converted by the frequency converter into each of the receivers of the two adjacent branches, and finds as a first ratio the ratio of a plurality of amplitude and phase values respectively measured at the receivers of two adjacent branches, and at the same time, for branches other than that assigned in advance to serve as the reference, the first ratio found at the relevant branch is calibrated using the first ratio found at the other branches, and the calibration value of the receiving system of each of the branches is calculated.
For each of two adjacent branches, the signal from one of the receivers is alternately selected at the second switch and input into one of the receivers, and thereby two amplitude and phase values are obtained. The ratio of these two amplitude and phase values serves as the first ratio. The first ratio is found for each of the respective adjacent branches.
Amplitude and phase value components related to the receivers of the two branches are included in the first ratio found between two adjacent branches. Thus, for branches other than that assigned in advance to serve as the reference, the first ratio found at the relevant branch is calibrated using the first ratio found at the other branches.
By this calibration, the first ratio of each of the branches is unified with the ratio of the amplitude and phase values of the receiver of the relevant branch with respect to the amplitude and phase value components of the receiver of the particular branch assigned to serve as the reference. Therefore, the first ratio of each of the branches can be used as a calibration value for the amplitude and phase value components of each of the receivers.
In addition, in an adaptive array antenna transceiver apparatus providing an array antenna formed by N antenna elements, N is an integral number and shows three or more; N transmitters and receivers; a transmitter/receiver common-use device that connects the respective transmitters and receivers to each of the antenna elements; and a radiation pattern control processor that controls the radiation pattern of the array antenna by synthesizing the output of the plurality of receivers by weighting the amplitude and phase with respect to a signal input from each of the respective antenna elements into the plurality of receivers, and at the same time the reception frequency of the array antenna to be used in communication and from the transmitting frequency is different, a fourth aspect of an adaptive array antenna transceiver apparatus provides N transmitters for which the frequency of the transmission signal is identical to the reception frequency of the array antenna; a first frequency converter that converts the frequency of signals transmitted by each of the N transmitters to the transmission frequency of the array antenna; N branching devices that extract a signal from the output of each of the N transmitters before conversion by the first frequency converter; N receivers for which the frequency of the reception signal is identical to the reception frequency of the array antenna; a second frequency converter that converts a signal having a frequency identical to the transmission frequency of the array antenna to a frequency identical to the reception frequency of the array antenna; an output of the first frequency converter; an input of the receiver; N first transmitter/receiver common-use devices provided between each of the antenna elements; N second transmitter/receiver common-use devices provided between, the output of the branching device, the input of the second frequency converter, and each of the antenna elements; at least one additional antenna that can be connected to any one of the N transmitters or the N receivers; a first switch provided on each of the antenna elements that connects either one of the antenna elements or the additional antenna to either one of the first transmitter/receiver common-use device or the second transmitter/receiver common-use device; a second switch provided on each receiver and connected to the input of the receivers and selectively inputs into the receivers either one of the reception signals from the first transmitter/receiver common-use device or the reception signals output by the second frequency converter; a third switch that connects the additional antenna to any one of the first switches; and a calibration control circuit that controls the first switch, second switch, and third switch, and at the same time finds the calibration value of the amplitude and phase between branches of the array antenna based on the amplitude and phase values obtained from each of the receivers.
In the fourth aspect of the adaptive array antenna transceiver apparatus, by controlling the first switch, second switch, and third switch, the circuits of three branches are selected, and a signal transmitted from each of two branches can be received by the one common branch or the signal transmitted from the one common branch can be received by each of the two remaining branches.
In addition, a signal can be transmitted or received using the additional antenna for the common branch.
The additional antenna is disposed at a predetermined position, and by receiving at the one common branch a signal transmitted from two branches via the additional antenna, the relative amplitude and phase values that include the transmitting part 115 and antenna elements of the two branches can be found as the calibration value.
In addition, by receiving the signal transmitted from the one common branch at the two respective branches via the additional antenna, the relative amplitude and phase values that includes the reception part and the antenna elements of the two branches can be found as the calibration value.
Because the reception frequency and transmission frequency of the array antenna used for communication are different, the frequency of the signal transmitted from the array antenna is different from the reception frequency of the receiver, but the receiver can obtain the reception signal having a receivable frequency due to the second frequency converter which is provided at the receiving side.
In addition, in the fourth aspect of the adaptive array transceiver apparatus, the calibration control circuit controls the first switch, second switch, and third switch, and selects from among the N transmitters the first transmitter or the second transmitter respectively included in branches of two antenna elements that have equal distances from the additional antenna, and at the same time, selects from among the N receivers one calibration receiver included in a branch differing from that of the first transmitter and the second transmitter, connects the third switch to one calibration receiver included in a branch differing from that of the first transmitter and second transmitter, transmits the signal that is the signal transmitted by the first transmitter and frequency converted by the first frequency converter from the antenna element of the branch included in the first transmitter, inputs the output that is the signal from the first transmitter received by the additional antenna and frequency converted by the second frequency converter into the calibration receiver, and detects a first measured value obtained at the calibration receiver, transmits the signal that is the signal transmitted from the second transmitter and frequency converted by the first frequency converter from the antenna element included in the second transmitter, inputs the output that is the signal from the second transmitter and received by the additional antenna and frequency converted by the second frequency converter into the calibration receiver and detects the second measured value obtained at the calibration receiver, calculates the ratio of the second measured value and the first measured value to serve as the first calibration value, finds the first calibration value for the respective plurality of branches based on the first measured value and the second measured value measured by switching in sequence the selection of the first transmitter an the second transmitter, and for branches other than the reference branch assigned in advance, calibrates the first calibration value of the relevant branch using the first calibration value obtained at the other branches, and calculates the relative value with respect to the reference branch as the first calibration value.
In the fourth aspect of the adaptive array antenna transceiver apparatus, the calibration control circuit controls the first switch, second switch, and third switch, and selects from among the N transmitters a first transmitter and the second transmitter included in the respective branches of two antenna elements that have equal distances from the additional antenna, and at the same time, selects from among the N receivers one calibration receiver included in a branch different from that of the first transmitter and second transmitter.
In addition, the calibration control circuit transmits the signal that is the signal transmitted from the first transmitter and frequency converted by the first frequency converter from the antenna element of the branch included in the first transmitter, inputs the output that is the signal from the first transmitter received by the additional antenna and frequency converted by the second frequency converter into the calibration receiver, and detects the first measured value obtained at the calibration receiver.
Furthermore, the calibration control circuit transmits the signal that is the signal transmitted by the second transmitter and frequency converted by the first frequency converter from the antenna element of the branch included in the second transmitter, inputs the output that is the signal from the second transmitter received by the additional antenna and frequency converted by the second frequency converter into the calibration receiver, and detects a second measured value obtained at the calibration receiver.
In addition, the calibration control circuit calculates as the first calibration value the ratio of the second measured value and the first measured value, and finds the respective first calibration values for the plurality of branches based on the respective first measured value and the second measured value by switching in sequence the selection of the first transmitter and the second transmitter. In addition, for branches other than the reference branch assigned in advance, the first calibration value of the relevant branch is calibrated using the first calibration value obtained at the other branches, and the first calibration value is calculated as a relative value with respect to the reference branch.
In the above-described fourth aspect of the adaptive array antenna transceiver apparatus, even in the case that there are many antenna elements in the array antenna, the calibration value for the amplitude and phase values of the transmitter that includes the transmitters and antenna elements of the respective branches can be found as a relative value with respect to a particular reference branch.
In addition, in the fourth aspect of the adaptive array transceiver apparatus, the calibration control circuit controls the first switch, second switch, and third switch, and selects from among the N transmitters the first transmitter or the second transmitter respectively included in branches of two antenna elements that have equal distances from the additional antenna, and at the same time, selects from among N transmitters one calibration transmitter included in a branch different from that of the first receiver and the second receiver, transmits the signal output by the calibration transmitter from the additional antenna via the branching device, the second transmitter/receiver common-use device, the first switch, and the third switch, inputs the signal from the calibration transmitter received by the antenna element of the branches included in the first receiver into the first receiver and detects the first measured value obtained at the first receiver, inputs the signal from the calibration transmitter received by the antenna element of the branch included in the second receiver into the second receiver and detects a second measured value obtained at the second receiver, calculates the ratio of the second measurement value and the first measurement value as the first calibration value, finds the first calibration values of the respective plurality of branches based on the first measured value and the second measured value respectively measured by switching in sequence the selection of the first receiver and second receiver, calibrates the fist calibration value of the relevant branch using the first calibration value obtained at the other branches, and calculates the first calibration value as a relative value with respect to the reference branch.
In the fourth aspect of the adaptive array antenna transceiver apparatus, the calibration control circuit controls the first switch, second switch, and third switch, and selects from among N receivers the first receiver and second receiver respectively included in branches of two antenna elements that have equal distances from the additional antenna, and at the same time, selects from among N transmitters one calibration transmitter included in a branch different from that of the first receiver and the second receiver.
In addition, the calibration control circuit transmits a signal output by the calibration transmitter from the additional antenna via a branching device, a second transmitter/receiver common-use device, a first switch and third switch, inputs the signal from the calibration transmitter received by the antenna element of the branch included in the first transmitter into the first receiver, and detects the first measured value obtained at the first receiver.
Furthermore, the calibration control circuit inputs a signal from the calibration transmitter received by the antenna element of a branch included in the second receiver into the second receiver, and detects the second measured value obtained at the second receiver.
In addition, the calibration control circuit calculates the ratio of the second measured value and the first measured value as the first calibration value, and finds the first calibration value for the respective plurality of branches based on the respective first measured value and the second measured value by measured by respectively switching in sequence the first receiver and the second receiver. In addition, for branches other than the reference branch assigned in advance, the calibration control circuit calibrates the first calibration value for the relevant branch using the first calibration value obtained at the other branches, and calculates the first calibration value as a relative value with respect to the reference branch.
In the above-described fourth aspect of the adaptive array antenna transceiver apparatus, even in the case that there are many antenna elements in the array antenna, the calibration value of the amplitude and phase values of the reception part that includes the receiver and antenna elements of the respective branches can be found as a relative value with respect to a particular reference branch.
In addition, in the fourth aspect of the adaptive array antenna transceiver apparatus, the present invention disposes N antenna elements at an equal distance on one straight line, and at the same time, disposes an additional antenna at a position at the middle of two antenna elements.
In the case that the antenna elements of the array antenna are disposed in a line, by placing the additional antenna at a position at the middle of the two selected antenna elements, the distances between the two respective antenna elements can be made equal.
By making the respective distances between the additional antenna and the two antenna elements equal, the calibration value can be found such that the influence of transmission loss between the antenna elements and the additional antenna does not appear.
Moreover, in the case that the calibration value is found for each of three or more branches, the position of the one additional antenna can be modified depending on the arrangement of the selected branches, or a plurality of additional antennas can be disposed in advance at positions at the middle thereof and then the plurality of additional antennas switched by a switch.
In addition, in the fourth aspect of the adaptive array antenna transceiver apparatus, the present invention disposes N antenna elements at equal distances on a circle, and at the same time, disposes the additional antenna at the center position of the circle.
In the case that the antenna elements of the array antenna are disposed arranged on a circle, by disposing the additional antenna at the middle position of this circle, the distances between all the respective antenna elements and the additional antenna can be made equal.
In addition, in an adaptive array antenna transceiver apparatus providing an array antenna formed by N antenna elements, N is an integral number and shows two or more; N transmitters and receivers; a transmitter/receiver common-use device that connects the respective transmitters and receivers to each of the antenna elements; and a radiation pattern control processor that controls the radiation pattern of the array antenna by synthesizing the output of the plurality of receivers by weighting the amplitude and phase with respect to a signal input from each respective antenna element into the plurality of receivers, and at the same time the reception frequency of array antenna to be used in communication and the transmitting frequency are different, a fifth aspect of an adaptive array antenna transceiver apparatus provides N transmitters for which the frequency of the transmission signal is identical to the reception frequency of the array antenna; a first frequency converter that converts the frequency of signals transmitted by each of the N transmitters to the transmission frequency of the array antenna; N first branching devices that extract a signal from the output of each of the N transmitters before conversion by the first frequency converter; N second branching devices that extract a signal form the first frequency converter after conversion at each of the branches of the array antenna; N receivers for which the frequency of the reception signal is identical to the reception frequency of the array antenna; a second frequency converter that converts a signal having a frequency identical to the transmission frequency of the array antenna to a frequency identical to the reception frequency of the array antenna; N first transmitter/receiver common-use devices provided between the output of the first frequency converter, the input of the receiver, and each of the antenna elements; an output of the branching device; an input of the second frequency converter; N second transmitter/receiver common-use device provided between each of the antenna elements; at least one additional antenna that can be connected to any one of the N transmitters or the N receivers; a first switch provided on each of the antenna elements that connects either one of the antenna elements or the additional antenna to either one of the first transmitter/receiver common-use device or the second transmitter/receiver common-use device; a second switch that connects the output of the first branching device included in the reference branch assigned in advance to the input of the receiver in any one branch; a third switch that connects any one of the outputs of the N second branching devices included in each of the branches to the input of the second frequency converter included in the reference branch; the output of a third switch; a fourth switch that connects any one of the second circulators included in the reference branch to the input of the second frequency converter included in the reference branch; a fifth switch that, in each of the branches, selects any one of the reception signals from the first transmitter/receiver common-use device, the signal output by the second frequency converter, or the signal from the transmitter output by the second switch, and applies it to the input of a receiver; a sixth switch that connects the additional antenna to any one of the first switches; and a calibration control circuit that controls the first switch, second switch, third switch, fourth switch, fifth switch, and sixth switch, and at the same time finds the amplitude and phase calibration values between branches based on the amplitude and phase values obtained from each receiver.
In the fifth aspect of the adaptive array antenna transceiver apparatus, by controlling the first switch, second switch, third switch, fourth switch, fifth switch, and sixth switch, the transmitting and receiving of signals can be carried out between a reference branch and one selected branch without interposing an antenna element.
This means that in the case of measuring the calibration value of a receiver, the signal output by the first frequency converter of the reference branch and the selected branch is selectively input into the receiver of the reference branch via the second branching device, the third switch, the fourth switch, the second frequency converter, and the fifth switch, and thus for the respective reference branch and the selected branch, the amplitude and phase values of the transmitter can be measured at the receiver of the reference branch. Therefore, a calibration value of a receiver that does not include the antenna can be found as a relative value with respect to the reference branch.
In addition, in the case that the calibration value of the receiver is measured, the signal that is output by the transmitter of the reference branch passes the first branching device and the second switch, then passes the reference branch and the selected branch of the fifth switch, and is then input into the receiver of each of the branches, and thus the signal from the transmitter of the reference branch can be measured at the receivers of the reference branch and the selected branch without interposing an antenna element. Therefore, a calibration value of a receiver that does not include the antenna can be found as a relative value with respect to the reference branch.
In addition, in an adaptive array antenna transceiver apparatus that provides an array antenna formed by N antenna elements, N is an integral number and shows two or more; N transmitters and receivers, a first transmitter/receiver common-use device that respectively connects the transmitter and receiver to each of the antenna elements, and a radiation pattern control processor that controls the radiation pattern of the array antenna by synthesizing the output of the plurality of receivers by weighting the amplitude and phase with respect to a signal input from each respective antenna element to the plurality of receivers, and at the same time, the reception frequency and the transmission frequency of the array antenna used in communication are different, and the frequency of the signal output by each of the transmitters is f1 and the reception frequency of each of the receivers is f2, a sixth aspect of an adaptive array antenna transceiver apparatus provides at least one additional antenna disposed at a position such that the distance between at least two antenna elements of the array antenna is equal; a second transmitter/receiver common-use device connected to the additional antenna; at least one first frequency converter that converts the signal having a frequency of f1 output from one transmitter to the frequency f2 and inputs it into the second transmitter/receiver common-use device, and at the same time converts the signal having a frequency of f1 input from the second transmitter/receiver common-use device to a frequency f2 and outputs it; at least one branching device that inputs into the frequency converter the signal extracted from at least one output of the N transmitters; at least one first switch that connects the input of at least one of the N receivers to any one of the first transmitter/receiver common-use devices and frequency transformers; and a calibration control circuit that controls the first switch and finds the amplitude and phase calibration values between branches of the array antenna based on the amplitude and phase values obtained from each of the receivers.
In the sixth aspect of the adaptive array antenna transceiver apparatus, by carrying out transceiving of a signal between the antenna elements of each of the branches using the additional antenna, the amplitude and phase values of each of the branches can be detected.
Because the frequency f1 of the signal output by each of the transmitters and the received frequency f2 at each of the receivers are different, the signal transmitted by the transmitter cannot be detected as-is at the receiver. However, because the signal having frequency f1 output by the transmitter during calibration is converted to a signal having frequency f2 by a frequency converter before being transmitted from the additional antenna or after being received by the additional antenna, the receiver can detect this signal.
By switching the first switch, the signal received by the additional antenna and the signal received by the antenna elements of the array antenna are selected and can be input into the receiver.
In addition, in the sixth aspect of the adaptive array antenna transceiver apparatus, a second switch that connects the branching devices to the respective output of the N transmitters, connects the first switch to the respective inputs of the N receivers, and furthermore, selectively connects any one of the branching devices connected to the N transmitters to the input of the frequency converter, and the third switch that selectively connects the output of the frequency converter to any one of the first switches connected to the N receivers are provided.
In the sixth aspect of the adaptive array antenna transceiver apparatus, the signal output by the respective N transmitters can be selectively input into the frequency converters and frequency converted. In addition, the signal having a frequency f2 output from the frequency converter can be selectively input into the receiver of any branch.
Thus, calibration can be carried out without using either the antenna elements of the array antenna or the additional antenna.
In addition, in the sixth aspect of the adaptive array antenna transceiver apparatus, the calibration control circuit controls the first switch, connects the output of the frequency converter to the input of the one receiver assigned to the selected calibration receiver from among the N receivers, selects in sequence one of the N transmitters to be a calibration transmitter and transmits the signal from the calibration transmitter, inputs the signal transmitter from the calibration transmitter and transmitted via the first transmitter/receiver common-use device and the antenna element connected thereto to the calibration receiver via the additional antenna, the second circulator, the frequency converter, and the first switch, and finds the amplitude and phase calibration values between branches of the array antenna based on the measured values detected at the calibration receiver for the signal transmitted from the calibration transmitter of the respective branch.
In the sixth aspect of the adaptive array antenna transceiver apparatus, the signals from the calibration transmitters selected in sequence can be transmitted by control of the calibration control circuit. These signals are transmitted via the first circulator and the antenna elements connected thereto, and received at the additional antenna. The signal output from the additional antenna is input into the calibration receiver via the second transmitter/receiver common-use device, the frequency converter, and the first switch.
Therefore, the signals transmitted from the calibration transmitters of the respective branches can be detected at the calibration receiver via the antenna.
In addition, in the sixth aspect of the adaptive antenna array transceiver apparatus, in the present invention, the calibration control circuit controls the first switch, connects the input of the receiver connected thereto to the first transmitter/receiver common-use device, assigns one of the N transmitters to be a calibration transmitter and transmits the signal from the calibration transmitter, selects in sequence one of the N receivers to be the calibration receiver, inputs a signal transmitted from the calibration transmitter and transmitted from the additional antenna through the branching device, a frequency converter, and a second transmitter/receiver common-use device, and finds the amplitude and phase calibration values between branches of the array antenna based on the measured values detected at the calibration receivers of the respective branches.
In a sixth aspect of the adaptive array transceiver apparatus, by the control of the control circuit, the signal transmitted from the calibration transmitter passes through the branching device, the frequency converter, and the second transmitter/receiver common-use device, and is transmitted from the additional antenna. This signal is input into the respective calibration receivers via the antenna elements of the branch and the first circulator selected in sequence.
Therefore, the signal transmitted from the first calibration transmitter can be detected at the respective calibration receivers via the path passing through the antenna of each of the branches.
In addition, in the sixth aspect of the adaptive array antenna transceiver apparatus, in the present invention, the calibration control circuit controls the first switch, connects the output of the frequency converter to the input of the one receiver among the N receivers assigned to be the calibration receiver, selects in sequence as a calibration transmitter one of the N transmitters and transmits the signal from the selected calibration transmitter, splits the signal transmitted from the calibration transmitter by the branching device and inputs the result into the frequency converter via the second switch, applies the signal output by the frequency converter to the input of the calibration receiver via the third switch and the first switch, and finds the amplitude and phase calibration values between the branches of the array antenna based on the measured values detected by the calibration receiver for the signal transmitted from the calibration transmitter for the respective branches.
In the sixth aspect of the adaptive array antenna transceiver apparatus described above, by controlling the calibration control circuit, respective signals are transmitted from the calibration transmitters selected in frequency. These signals are split by a branching device and input into the frequency converter via the second switch. The signal output from the frequency converter is applied to the input of the calibration receiver via the third switch and the first switch.
Therefore, the signals transmitted from the calibration transmitters of the respective branches can be detected at the calibration receiver via the path not passing through the antenna.
In addition, in the sixth aspect of the adaptive array antenna transceiver apparatus, the present invention is characterized in the calibration control circuit assigning one of the N transmitters to be the calibration transmitter and transmitting a signal from that calibration transmitter, selecting in sequence one of the N receivers to be the calibration receiver, splitting signals transmitted from the calibration transmitter by a branching device and applying them to the input of the frequency converter via the second switch, applying the signal output from the frequency converter to the input of the calibration receiver via the third switch and the first switch, and finding the amplitude and phase calibration values between branches of the array antenna based on the measured value detected at the calibration receivers of the respective branches.
In the sixth aspect of the adaptive array antenna transceiver apparatus described above, by controlling the calibration control circuit, a signal from one calibration transmitter is transmitted. This signal is separated by the branching means and applied to the input of the frequency converter via the second switch. The signals output from the frequency converter are applied in sequence to the input of the calibration receiver of the selected branches via the third switch and the first switch.
Therefore, the signals transmitted from one calibration transmitter can be detected in sequence by the calibration receiver of the respective branches via the path not passing through the antenna.
In addition, in the sixth aspect of the adaptive array antenna transceiver apparatus, the present invention provides a first frequency converter in which the signal having the frequency f1 output from one transmitter is converted to a signal having the frequency f2, and a transmitter/receiver common-use device frequency converter in which a signal having a frequency f1 input from the second circulator is converted to a signal having a frequency f2.
In the sixth aspect of the adaptive array antenna transceiver apparatus described above, the first frequency converter for converting the frequency of the signal transmitted to the additional antenna and the second frequency converter for converting the frequency of the signal received at the additional antenna are independent. Thus, the number of switches for switching the input and output of the frequency converter can be decreased.
In addition, in the sixth aspect of the adaptive array antenna transceiver apparatus, the present invention disposes the N antenna elements on one straight line, and in addition, disposes the additional antenna at a position at the middle of two antenna elements.
By disposing the N antenna elements and the additional antenna in this manner, the distance between at least two of the antenna elements and the additional antenna can be made equal.
Moreover, in the case that a plurality of additional antennas are provided, respective antenna elements are disposed such that the distances between two antenna elements are equal, and the plurality of additional antennas can be switched by the switches.
In addition, in the sixth aspect of the adaptive array antenna transceiver apparatus, the present invention disposes N antenna elements at equal intervals on one circle, and at the same time disposes an additional antenna at the center position of the circle.
By disposing the N antenna elements and additional antenna in this manner, all of the distances between the additional antenna and the N antenna elements are made equal.